High-frequency wiring board

Abstract

There has been a problem that a mode (a high-order mode) different from a basic propagation mode occurs at a point of a through conductor and a transmission characteristic deteriorates greatly. The present invention is a high-frequency wiring board wherein L>lambd / 4 and pi(A+B)<=lambd are satisfied in which L is a length of a through conductor, A is a diameter of the through conductor, B is shortest distances between the through conductor and a plurality of ground through conductors, pi is a circle ratio and lambd is an effective wavelength of a high-frequency signal transmitted by the through conductor. It is possible to inhibit a high-order mode which occurs at a point of the through conductor.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to a high-frequency wiring board for connecting and mounting a high-frequency integrated circuit or a high-frequency circuit device such as an IC and an LSI used in a high-frequency region of a millimeter waveband of 30 GHz or more, and more specifically, relates to a high-frequency wiring board which has a through conductor for signal transmission with an improved high-frequency signal transmission characteristic.[0003] 2. Description of the Related Art[0004] As a conventional high-frequency wiring board which transmits a high-frequency signal, there is one which is shown in a section view of FIG. 7 and a plan view of FIG. 8, for example.[0005] In FIGS. 7 and 8, reference numeral 21 denotes a high-frequency wiring board, reference numerals 22a to 22d denote dielectric layers, a first line conductor 23 and a second line conductor 24 are disposed to main faces 29a, 29b of the high-frequency wiring board 21, and one ...

AI Technical Summary

Benefits of technology

[0023] According to the invention, as a result that distances between the ground conductors and the same plane ground conductors, that is, connection lengths of the ground through conductors electrically connecting the ground conductors and the same plane ground conductors are made to be short enough with respect to a wavelength of a high-frequency signal, it is possible to inhibit potential distribution which occurs in the respective ground through conductors, so that it is possible to stabilize ground potential of the ground through conductors, and consequently, it is possible to realize a good transmission characteristic in a high-frequency signal of a millimeter waveband.

[0025] According to the invention, a distance between the centers of the ground through conductors is short enough with respect to an effective wavelength of a high-frequency signal, it is possible to inhibit spread of an electromagnetic field from between the ground through conductors, and therefore, it is possible to further inhibit unnecessary radiation of a high-frequency signal from between the ground through conductors, with the result that it is possible to realize a good transmission characteristic in a high-frequency signal of a millimeter waveband.

[0027] As described above, according to the invention, it is possible to provide a high-frequency wiring board which is capable of inhibiting a high-order mode occurring at a point of the through conductor and enables obtaining a good transmission characteristic in a high-frequency signal of a millimeter waveband of 30 GHz or more.

Problems solved by technology

This high-frequency wiring board has a problem that because a frequency of a high-frequency signal becomes higher in recent years, unnecessary radiation of a high-frequency signal occurs from between the ground through conductors 27, with the result that radiation loss of a high-frequency signal increases and a transmission characteristic deteriorates.

However, the above conventional high-frequency wiring board has a problem that although unnecessary radiation of a high-frequency signal from between the ground through conductors is inhibited as a result of increasing the number of the ground through conductors, a wavelength is short in a high-frequency region of a millimeter waveband, and therefore, a mode (a high-order mode) different from a basic propagation mode occurs at a point of the through conductor in a case where the length of the through conductor is .lambda. / 4 or more, with the result that a transmission characteristic deteriorates greatly as a frequency becomes higher.

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